Singlet molecular oxygen by direct excitation.

Direct excitation at 1064 nm and detection of singlet molecular oxygen at 1270 nm is made possible by the availability of powerful YAG-lasers and sensitive NIR photomultipliers. Singlet oxygen was generated in condensed phase at 77 K by direct excitation at 1064 nm (without the use of sensitizers). Several luminescing species were observed by time resolved luminescence spectroscopy and luminescence lifetime measurements, including the single molecule (1)Delta(g)and (1)Sigma(g)(+)states as well as luminescence from the [(1)Delta(g)](2) simultaneous transition. As an application we propose a novel method for obtaining quantitative non-intrusive mapping of the 2-D oxygen concentrations and pressure at cryogenic temperatures, which is of importance in aircraft design for high altitudes.